Am I doing the right thing??

Ta
I'm babysitting two boys, 5 and 2 (there are two more but they are with their relatives) and I put them to bed and the 5 year old has been screaming because I won't let him watch his kindle, even though its Christmas break, in bed because I wasn't told if this was ok or not with his parents.
He's been fine the past few months I've been watching them and has gone to bed no problem when I say bedtime and this is the first time he's been acting up.
I know they were watching a movie and it's their parents a few days ago and it frightened him (the new Tim Burton movie) and said his mom sometimes lets him watch the kindle in bed but I wasn't told by his parents if this was ok so I don't want to make that decision and he's the fibber of the group, plus he said they didn't let him sleep with it yesterday; but if they say they were and I took his right away, I'm going to feel bad :/.
There's no way of me calling to ask either because they are seeing a movie.
I don't want to just give him what he wants but I'm going to feel bad if he really was allowed and I basically took it away.